Thrift Savings Plan and Service Members' Group Life Insurance are classified as what?

The classification of Thrift Savings Plan (TSP) and Service Members' Group Life Insurance (SGLI) as voluntary deductions is accurate because participation in these programs is not mandatory for employees or service members. Instead, individuals have the option to enroll in and contribute to the TSP, which is a retirement savings plan, as well as choose the coverage level for SGLI, which provides life insurance benefits.

This voluntary nature allows individuals to decide based on their financial goals and personal circumstances whether or not to participate in these programs, unlike mandatory deductions, which are pre-determined and automatically deducted from paychecks, such as federal and state taxes or Social Security contributions. The other classifications do not apply because they either refer to different concepts (like allowances which provide additional compensation) or to types of investment vehicles that don't pertain directly to the structure of these specific programs.